Abstract:

The effects of running buffer on reproducibility of the migration time in the modes of
capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC)
were investigated. The parameters include concentration, pH value and the properties change of the
running buffer. The results showed that the reproducibility of migration times may be improved
through three approaches. First, the correlation between running buffer concentration and migration
time was established and the running buffer concentration was determined by conductivities in order
to improve the reproducibility. Second, it was found that the residual running buffer in the
capillary showed significant influence on the repeatability of migration times. Thus, appropriate
running or washing procedure between separations is necessary. Finally, the inlet reservior buffer
plays an extremely important role in affecting the migration behaviors of solutes. Through improving
the test apparatus, reproducible migration time was achieved as a result of increasing the frequency
of replacing the buffer in the inlet reservior.

Key words: micellar electrokinetic capillary chromatography
（MECC）； migration time； reproducibility； running buffer , capillary zone electrophoresis （CZE）